1. Field
Exemplary embodiments relate to optical zoom probes, and more particularly, to optical zoom probes in which scanning may be performed both in a near distance and in the nearest distance.
2. Description of the Related Art
In the field of medical imaging, demands for performing tomography using information regarding the surface of a tissue (human body or skin) are increasing. In particular, because most types of cancers are generated in lower parts of epithelial cells and are propagated into dermal cells in which blood vessels exist, when cancer can be detected at an early stage, damage caused by cancer can be remarkably reduced. With respect to existing imaging techniques, such as magnetic resonance imaging (MRI), x-ray computed tomography (CT), and ultrasonic waves, although tomography can be performed on an inside of a tissue by penetrating the skin, early detection of cancer which involves a tumor having a small size cannot be performed due to low resolution. Conversely, because light is used in performing an optical coherence tomography (OCT) technique that has been recently introduced, unlike in the existing art, the depth of penetration into the skin is low, i.e., about 2 to 3 mm, and resolution is high, about 10 times better than the resolution of ultrasonic waves. Thus, the OCT technique is expected to be useful in diagnosing early stages of cancer which involve a tumor having the size of about 50 to 100 μm. However, because the resolution of the OCT technique is lower than that of a microscope, the OCT technique cannot replace biopsy and histology that are actually used for making conclusive determinations relating to cancer diagnoses.
Recently, some OCT researchers have conducted investigations relating to performing diagnosis of cancer inside a tissue in real-time by combining tomography characteristics of OCT and high-resolution surface photographing using a confocal microscope, for example, and without performing biopsy. However, an objective lens of the microscope requires an optical system with a high numerical aperture (NA) so as to realize a high resolution in a horizontal direction, whereas OCT requires an optical system which has relatively uniform spot sizes in a depth direction, i.e., having a large depth of focus (DOF) with a low NA.